330hp_91RS

I was just wondering if I am supposed to make the piece shorter or longer. My total drop will be 1.75 all the way around, so I was also wondering approximately how much shorter or longer to make it, i.e. 3/4 inch, 1 inch, etc.

I am preety sure that it needs to be lengthened but second opinions always help, especially from you guys who have already done it.

RB83L69

Just get up under your car and look. However far the rear will move to one side when lowered, that's how much you need to adjust its length.

I seriously doubt it would change by more than ¼" from stock ride height, given that the bar is very close to level.

Dewey316

for lowered cars you should SHORTEN , but like it said before, get under there and look, if the rear end sticks to the drivers side, the panhard needs to be shortened, and if it sticks to the pass side, it needs to be lengthened.

bennyhonda

I had to lengthen mine when I installed my Pro Kit. It was only about 1/4-1/2 inch though.

I don't know why you would shorten it, unless you had previously raised/lowered the back of the car and were returning closer to stock. Make it a right triangle and you can see why.

A = The horizontal leg = your stock length panhard bar(level with stock springs),
B = the vertical leg = the change in the height of the body mount(.75-2" depending on springs)
C = the hypothenuse = the length for your panhard bar with lowering springs(since the body drops the panhard bar no longer mounts level). A^2 + B^2 = C^2.

Maybe I'm missing something where thirdgens don't follow the rules of geometry.

swerve-driver

The panhard is attached at a fixed, immovable point on the body (upper passengers side). When lowering springs are installed, the opposite end (drivers side- attached at axle) of the panhard rod will swing up, effectively extending it's length. This would in turn shift the rear end of the car to the drivers side slightly.

Therefore, it would need to be shortened.......in theory.

In theory, communism works.

Your results may vary.

Best-
S-D

bennyhonda

When the mounts are level, you have only the horizontal measurement between the mounts, no vertical thus the shortest distance. When the mounts aren't level, you have horizontal and vertical measurements creating a triangle with the panhard bar as the hypothenuse. Since the stock panhard bar is now too short, your rear end will be shifted to the passenger side.

Hands on exercise: Take a fixed length object, a pen or pencil, hold it level in both hands now move one hand up or down. What happens? Either the pen falls out of one hand or your hands get closer horizontally.

BretD 88GTA

No theory involved. That is indeed what takes place. When lowering the car, the rear axle will shift slightly toward the driver's side. SHORTENING the panhard bar will re-align the rearend.

This should be done on the car. You'll have a tough time trying to estimate how much to shorten the bar until you get it installed. That's what's so nice about the Spohn PHB. On car adjustment is VERY easy. With other brands you have to disconnect one end of the bar, adjust it, re-connect it, check it, disconnect it, adjust it agin, re-connect it, and so on till you get it right.

It should only take one or two trys, but still IMHO, it's kind of a PITA. Go with Spohn and you'll have zero hassels.

swerve-driver

Bret-
Very concise. Thanks for the backup.

My car is lowered. I do not have the adjustable bar. In a weird coincidence, I inadvertently shortened my panhard by welding bracing onto it (I laid a 3/8" steel rod in the groove and sticth welded it). After welding, I noticed it bowed a little (a camber type bow, not side to side). It shortened the length by about 1/4", which turned out just about right.

Absolutely no theory there, just some good luck!

Best-

S-D

Bennyhonda- your triangle logic is correct, but you are, in effect, talking about increasing ride height (that is, moving the panhard bar further away from true horizontal) not decreasing ride height, which is what happens with lowered springs.

Best-
S-D

bennyhonda

Whether the car moves up or down, the panhard bar is still moving away from true horizontal. It's level at stock height, so 2" higher or 2" lower gives you the same angles.

I went out and measured my panhard bars. My adjustable bar is currently 43.25" to bolt centers and probably needs another 1/8" or so, just eyeballed it when I installed it a few weeks ago. The stock bar in my garage measured an even 43" to bolt centers.

Anyway I'm done. The difference is negligable.

Zepher

iTrader: (1)

I can't remember what I did to mine, but my car was offset about 1" to one side.
I am thinking that I had to shorten it and had some friends pushing the body of the car to one side so that I could get the bolt holes lined up. I was lowered about 2" with Jamex Springs.
I did it with the car on the ground. With the rear in the air, you could probably do it by yourself. Oh, and I had the Lakewood Adjustable and one side has to be unbolted from the car to adjust it. I've seen some with a turnbuckle in the middle which makes on the car adjustment easier, but I heard that those aren't as strong.

330hp_91RS

I have the same Lakewood. I was planning to put the rear frame of the car on jackstands and then put a jack under the rearend diff. to manuever it to line the bolt holes up. That Lakewood sure is a sturdy piece ain't it..especially for 93 bucks. Do you have the LCA's from lakewood? Are they just as sturdy?

AGood2.8

The problem you are facing is that you are not correct in your assumption that the panhard bar is exactly parallel to the ground at stock ride height- It is not. Fact of the matter is- if you lower the ride height about 2" the bar will then be parallel to the ground. I have had hands on experience with many f-bodys not just my own that all share this commonality- Yours may have been tweaked from an accident or such.

BretD 88GTA

Well, I guess every car is different. My car while at stockheight definitely did not have the PHB sitting level. It was higher at the point that attaches to the body, angling down to the axle connection.

After lowering the car with Jamex springs, the axle had shifted approximately 1/4" toward the driver's side. I adjusted my Spohn PHB to shorten the length and bring the rear axle back into alignment. I'd have to double-check, but IIRC my PHB is closer to being level after lowering the car.

Zepher

iTrader: (1)

Ya, I have the Lakewood LCA's. Really nice peices at an awesome price. They are really strurdy too,

Dirk

Are there any reference points on the car and axle that you can use to know whether or not the rear is aligned? With 2 good points, you'd be able to know when you're aligned when the distance between those points was equal so you wouldn't have to eyeball it

330hp_91RS

I had the hardest freakin time getting my bushings in the holes that were supplied with the lakewood panhard bar. How bout you!? Not te mention the damm grease fittings! I even used a rubber mallet and they still broke!

Hey: what kind of exhaust you got? ( muffler mainly )

AGood2.8

Your best bet on your own is to just set the LCA's at equal length to begin with. once on the car- if any adjustment need to be made positioning the axle forward or aft- just count the rotations of the adjustment sleeve equally left to right side.

Your best solution is to always have the car 4-wheel aligned on a rack- frames are never perfect to reference off of.

Zepher

iTrader: (1)

The bushings were hard but I got them in. The grease fittings took a couple of hits, but they all went in fine as well.

The exhaust on my car is a Pacesetter 3" Stainless steel catback, came right off of a 95 Trans Am Vert.
I don't have that anymore, traded my entire exhaust setup for the NOS Direct Port Nitrous kit.
I now have a flowmaster 80 series 3" catback with a 3" cutout and 96 Trans Am tips. this came off of a friends 96 Trans Am.

330hp_91RS

Parked the car on a level surface, took a measuring tape and a level, lined the level up and measured how far it was off. Adjusted the panhard bar 1/2 shorter, installed it. Done. Feels/rides great. Took me 1 hour.